1. Technical Field
The present invention relates to a magnetic disk recording device, and more particularly, to a method for optimizing a write current during a servowriting operation of a hard disk drive.
2. Related Art
In general, a magnetic disk recording device such as a hard disk drive ("HDD") and floppy disk drive ("FDD") is widely used in a computer system as an auxiliary memory. In particular, the HDD stores a large amount of data safely and permits data access at high speed.
Conventionally, the HDD is manufactured by a series of manufacturing processes including assembling the HDD.fwdarw.writing servo information.fwdarw.performing a function test.fwdarw.perfonning a burn-in test.fwdarw.combining HDA (Hard Disk Assembly) with PCBA (Printed Circuit Board Assembly).fwdarw.performing other tests. Generally, a servo information writing process involves writing positional information on a recording medium such as a magnetic disk, and the function testing process involves determining whether a maintenance cylinder is defective and whether a data area is readable/writable. The burn-in testing process requires determining whether the data area is defective.
In more detail, during the servo information writing process, a servo writer moves a head (data transducer) of the HDD in a predetermined direction and distance in order to write a variety of servo information (or positional information) for controlling a position of the head on the disk. The servo information written has tremendous influence not only on a track searching performance but also on a track tracing performance during servo control operation. This is because the track searching and track tracing control operations depend heavily on the servo information written for maintaining high data read/write performance. As a result, the quality of HDD is dependent upon the servo writing feature.
Generally, a write current applied equally to each HDD during the servo writing operation is adjusted at an initial stage in order to optimize the performance of the head and disk. The performance of the head and disk which are principal components of the HDD is susceptible to the head stacking condition and the head assembling process. In particular, the amplitude, resolution, overshoot, undershoot, and etc. of the HDD are influenced differently at different locations from the inside and outside of the disk. Thus, even though the head and disk components are of good quality, an assembly thereof is not necessarily optimized for performance. Accordingly, I have noted that it is not appropriate to equally apply the like write current to the HDD for securing the optimal performance of every head and disk.
Exemplars of contemporary method of optimizing write current in a HDD are disclosed in U.S. Pat. No. 5,408,367 for Method Of Optimizing Operation Of Disk Drive issued to Emo, and U.S. Pat. No. 5,600,500 for Performance Based Write Current Optimization Process issued to Madsen et al. In Emo '367, for example, the write current is optimized by selecting the current level that has the lowest error rate based on calibration. In Madsen et al. '500, the write current is optimized by measuring a bit error rate in a HDD as a function of the write current in the presence of background interference stress and adjacent track interference stress. While the contemporary methods of optimizing operation of HDD are worthy optimization solution to servo writing operation, I believe that alternative techniques for optimizing write current during servo writing operation of a HDD are needed.